1. Field of the Invention
The present invention in general relates to a laryngoscope used as a medical instrument, and in particular, to an anesthetic laryngoscope with manual oxygen jet-ventilation means.
2. Description of the Related Art
It is well known in the art that a laryngoscope is used to expose a patient's glottis for tracheal intubation during cardiopulmonary resuscitation or induction of general anesthesia. Currently, the commonly used methods for opening the patient's airway during cardiopulmonary resuscitation are described as below.
Mouth-to-mouth artificial respiration is advantageous because of its immediate availability. However, this method may induce to exhaustion of the operator's physical strength during the operation and its effect is not reliable. In addition, this method has a possibility of spreading some diseases between the patient and the medical staff.
Esophagus obturator airway is convenient to use and is easily available. However, some potential complications such as apnea or gastric distention could be caused due to accidentally entering into the patient's trachea during the process. Therefore, esophagus rupture is likely to happen when the tube is drawn out without deflating the cuff. As for the patient whose respiratory reflex has not been restored, it is necessary or desirable to perform tracheal intubation to prevent regurgitation when the esophagus obturator airway is pulled out. The most serious disadvantage is that the face mask is very difficult to attach properly to the patient's face with the result that hyperventilation and hypercapnia may occur.
Tracheal intubation may be administered to maintain the airway unobstructed so that aspiration and stomach distention will not occur. After that, under an intermittent positive pressure ventilation may be carried out. Also, endotracheal suction can be performed directly. Therefore, tracheal intubation can be considered as a very reliable method for keeping the respiratory airway clear throughout the cardiopulmonary resuscitation.
However, tracheal intubation has some technical difficulties in use and takes a certain time (preferably not more than 15-20 seconds) to administer. At the same time, successful administration is subject to the influence of physical factors of the patient, such as an obese body, a short neck or a high laryngeal protuberance. Sometimes, although the larynx has been exposed, the glottis can not be seen clearly, thereby it is difficult to insert the tube. If the period of non-ventilation lasts too long, the tissue anoxia tends to be more serious. Thus, the patient's situation will be aggravated and the operation may end with unexpected failure.
In order to decrease death risk and increase the survival rate in such cases, the inventor has disclosed a multifunctional laryngoscope in his prior Chinese Patent No. 88203809.5, the disclosure of which is incorporated herein by reference.
That patent discloses an improvement on the conventional laryngoscope, in which a tank for storing drugs and a tube for supplying a jet of oxygen are provided. The purpose of the improvement is to provide a laryngoscope which can supply not only a stream of oxygen but also administer atomizing anesthesia in glottis during a tracheal intubation procedure. However, a drawback of that kind of laryngoscope is that it can not produce pulses during intubation in the cardiopulmonary resuscitation process so that jet ventilation can not be achieved.
If necessary, an open-type special jet respirator should be used in combination. The mechanism of this respirator switches the gas flow on and off by opening and closing an electromagnetic valve of the respirator to generate pulses of oxygen flow. An oxygen supply tube provided on the laryngoscope blade ejects a supply of oxygen flow in front of the exposing glottis so that streams of oxygen can enter into lungs and make hemithorax elevation until gas exchange can be achieved.
Since this open-type special ejection respirator is powered by storage batteries during field emergency treatment, it is bulky, heavy and expensive. In addition, it is not easy to carry while moving from one place to another. These drawbacks have virtually limited the scope of use of the laryngoscope in field emergency treatment. Although the open-type special ejection respirator is provided with manual oxygen blocking valve means to prevent the electromagnetic valve from being ineffective, it is necessary to involve an assistant to handle said valve means. Therefore, it is not convenient to use during the intubation procedure.